Hi,
I would guess, and it is only a guess, that the USB controller is Chinese. If it seems like I bash Chinese made controllers....
its because I do! They have earned all the bad press I give them.
Yes I would recommend an Ethernet connected controller and my suggestion would be an Ethernet SmoothStepper (ESS)
by Warp9. For Mach3 it is certainly not the only good (US or European made) controller, but it is what is familiar to me.
The ESS requires a breakout board, so one C10 ($23.00) or if you want/need more IO then a second one.
Without seeing inside the box we can't know whether the stepper drives are integrated onto on board, if I had to guess I
would say not. That being the case an ESS, a C10 and you can hook to your existing stepper drivers.
A Hypertherm 45 is probably a long term goal, Hypertherm is very good, probably the best on the market but they aren't cheap.
If the Razorweld is punematic contact break start as now seems likely then it should work OK, especially if it is recommended
by the table manufacturer. With any sort of luck by the time you blow the Razorweld up....and you will eventually.....you'll
have a swag of dough in the bank to buy a Hypertherm.
The first step is to get an Ethernet connected controller underway. I would guess that 50% of your problems will be solved right
there.
As for shielding and other measures....get set for the long haul....probably all of them will be required.
The first thing is to physically separate the cables associated with the plasma from any of the machine and signal wiring.
Where they cross they should be at right angles.
The second area that is often overlooked and therefore untold effort expended in other means to overcome is conducted noise.
The plasma being an inverter is a noisy device and draws non-sinusoidal current from the 230VAC supply. That non-sinusoidal
current can be many (10-30A) amps and that can be impressed on the 230VAC input to your PC and machine/controller
power supplies. One or several good AC line filters are in order four your PC and machine power supplies.
You could use a line reactor to tame the input current to the plasma but that is a fairly extreme step. I would save that for
'I'll only do it if I have to....later down the track' A line filter big enough to handle the plasma input current is likely to be
very expensive and that makes a line reactor more cost effective....should you need to.
You might try as an experiment to get your 230VAC for your plasma from a different and preferably remote socket from which
you get the 230VAC for your PC/machine. If it helps the line filters are strongly indicated.
https://nz.element14.com/schaffner/fn2090-6-06/filter-1-ph-6a-chassis-mount/dp/1304858?st=line filterNote I got that off the NZ website, depending on where you are Premier Farnell and/or Newark will have the same listing
in the local currency.
The next area you should look to is shielding signal cables, particularly cables such as limit and home switches. Their long length
makes then susceptible. They should be screened with all the screens earthed at one end only, usually the controller end with all
going to a single 'star point'. It is also good practice to fit ferrite cores, either by passing the cable through the core several times
or by using split cores. Two ferrites per cable, breaking the cable into approximately three equal sections has proven to work
for other installations.
https://nz.element14.com/fair-rite/2643804502/solid-round-emi-suppression-core/dp/1133951?st=EMI ferrites https://nz.element14.com/fair-rite/0446164181/ferrite-core-split-12-7mm-205ohm/dp/1781360You should have several ferrites on the Ethernet cable and even more importantly on any USB cable.
If you go with an ESS you will have the chance to add some de-bounce, effectively a digital input filter to all your incoming
signal lines. It is sometimes beneficial to have some 0.1nF ceramic capacitors on the inputs on your breakout board as well.
Quite a few installations have a separate earth stake just for the table. An electrical earth stake, or even more than one, if the
local earth impedance is high, are driven into the ground and connected to machine about where the torch sits.
Given that in New Zealand increasingly all circuits are protected by Residual Current Devices I am not enamored with the idea
of another earth stake in competition with the main electrical system, however so many people do it, so there must be some
benefit.
That's enough to start with.
Craig.